The present invention relates to a method and an arrangement for producing a workpiece by using additive manufacturing techniques. More particularly, the invention relates to a method and an arrangement for producing a workpiece by applying defined material layers step by step and one on top of the other.
Traditional manufacturing techniques are often based on removing material from a block of material by cutting, milling, drilling, grinding or other abrasive processes. These traditional manufacturing methods may be called subtractive manufacturing, because removal of the material is the core production step in the process.
The traditional subtractive manufacturing techniques offer a variety of capabilities which can nowadays be carried out at a high level of precision. The range of shapes that can be produced, however, is limited by the access of the abrasive tools to designed features. Other production techniques involve injection molding, casting and similar processes that use a mold where a workpiece is formed. These production processes can be very cost-efficient for high volume products, but they are often too expensive if only a small number of parts is required. In addition, the range of shapes that can be produced is again limited due to restrictions of the mold.
Therefore, additive manufacturing techniques have gained increasing interest not only for the manufacture of prototypes, but also as a promising new manufacturing technology in general. A variety of additive manufacturing techniques have been proposed including but not limited to Selective Laser Sintering, Selective Laser Melting, Fused Deposition Modeling and Stereolithography. These methods typically use heat or other sources of energy in order to selectively bind material particles thereby forming a material layer of the workpiece. After the production process, the workpiece is cooled down or will automatically cool down to ambient temperature. The temperature variations may lead to internal stress, tensions, warping caused thereby and/or shrinking with the result that it is very difficult to achieve manufacturing tolerances as they are known from today's subtractive manufacturing techniques. Potential in-processing variations might add and make it even more difficult to produce a workpiece that conforms to a predefined design within small tolerances.